Wind-Evoked Escape Running of the Cricket Gryllus Bimaculatus: II. Neurophysiological Analysis

1992 ◽  
Vol 171 (1) ◽  
pp. 215-245 ◽  
Author(s):  
MICHAEL HÖRNER
Keyword(s):  
Spike Activity ◽  
Cell Types ◽  
Companion Paper ◽  
Sensory Response ◽  
Dependent Manner ◽  
Suboesophageal Ganglion ◽  
Gryllus Bimaculatus ◽  
Sensory Responsiveness ◽  
Different Types ◽  
The Brain

Following the description of some typical variables of escape running in the cricket Gryllus bimaculatus in a companion paper, this study gives an account of the physiological characteristics of identified interganglionic cell types recorded during normal and wind-evoked walking. 1. Intracellular recording and staining of axons in the prothoracic ganglion revealed a group of intersegmental wind-sensitive neurones with large axons in the laterodorsal tract and somata in the pro- or mesothoracic ganglion. These interneurones rapidly conduct signals to their projections in the thoracic and cephalic ganglia. Wind pulses evoke strong, non-habituating spike reactions, which tend to summate during repeated stimulation. 2. During walking, the sensory response to wind stimulation is suppressed in a velocity-dependent manner in all ascending interneurones tested (N=40). During slow walking, the sensory responsiveness is merely reduced, whereas it is completely blocked during fast escape running bouts. Conversely, during pauses occurring during wind-evoked escape behaviour, the sensory responsiveness in ascending cells is significantly enhanced. 3. One type of interneurone that descends from the suboesophageal ganglion and projects to the thorax and abdominal connectives has been identified. In the resting animal, this neurone fires in the rhythm of abdominal ventilatory contractions. During walking, the rhythmic spike discharges disappear and, as in ascending interneurones, velocity-dependent spike suppression is observed. 4. In contrast to all other types of interneurones, which uniformly showed reduced spike activity during walking, cells descending from the brain were tonically excited during walking. Brain cells (N=21) have been classified according to whether their spike activity during walking was correlated with forward speed or with the intended walking direction. 5. Mechanisms underlying the observed gating of sensory responsiveness are discussed in terms of their possible functional significance. Modulated spike activity in ascending cells during walking suggests a role in tuning the thoracic motor centres for a central walking command. It is proposed that descending interneurones from the suboesophageal ganglion coordinate different behavioural rhythms. Possible functions of different types of brain neurones in the control of specific variables of walking behaviour are discussed.

scholarly journals Cytoadherence Properties of Plasmodium knowlesi-Infected Erythrocytes

2022 ◽  
Vol 12 ◽  
Author(s):  
Wenn-Chyau Lee ◽  
Shahhaziq Shahari ◽  
Samantha Yee Teng Nguee ◽  
Yee-Ling Lau ◽  
Laurent Rénia
Keyword(s):  
Endothelial Cells ◽  
Plasmodium Falciparum ◽  
Culture Supernatant ◽  
Plasmodium Knowlesi ◽  
Dependent Manner ◽  
Zoonotic Malaria ◽  
Different Types ◽  
Severe Pathology ◽  
Serum Dependent ◽  
The Brain

Plasmodium knowlesi is responsible for zoonotic malaria infections that are potentially fatal. While the severe pathology of falciparum malaria is associated with cytoadherence phenomena by Plasmodium falciparum-infected erythrocytes (IRBC), information regarding cytoadherence properties of P. knowlesi-IRBC remained scarce. Here, we characterized the cytoadherence properties of RBC infected with the laboratory-adapted P. knowlesi A1-H.1 strain. We found that late-stage IRBC formed rosettes in a human serum-dependent manner, and rosettes hampered IRBC phagocytosis. IRBC did not adhere much to unexposed (unstimulated) human endothelial cell lines derived from the brain (hCMEC/D3), lungs (HPMEC), and kidneys (HRGEC). However, after being “primed” with P. knowlesi culture supernatant, the IRBC-endothelial cytoadherence rate increased in HPMEC and HRGEC, but not in hCMEC/D3 cells. Both endothelial cytoadherence and rosetting phenomena were abrogated by treatment of P. knowlesi-IRBC with trypsin. We also found that different receptors were involved in IRBC cytoadherence to different types of endothelial cells. Although some of the host receptors were shared by both P. falciparum- and P. knowlesi-IRBC, the availability of glycoconjugates on the receptors might influence the capacity of P. knowlesi-IRBC to cytoadhere to these receptors.

scholarly journals Cellular Origin of Spontaneous Ganglion Cell Spike Activity in Animal Models of Retinitis Pigmentosa

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
David J. Margolis ◽  
Peter B. Detwiler
Keyword(s):  
Spike Activity ◽  
Ganglion Cells ◽  
Retinal Disease ◽  
Cell Types ◽  
Synaptic Activity ◽  
Retinal Ganglion ◽  
Spike Discharge ◽  
Cellular Origin ◽  
Effective Use ◽  
The Brain

Here we review evidence that loss of photoreceptors due to degenerative retinal disease causes an increase in the rate of spontaneous ganglion spike discharge. Information about persistent spike activity is important since it is expected to add noise to the communication between the eye and the brain and thus impact the design and effective use of retinal prosthetics for restoring visual function in patients blinded by disease. Patch-clamp recordings from identified types of ON and OFF retinal ganglion cells in the adult (36–210 d old)rd1mouse show that the ongoing oscillatory spike activity in both cell types is driven by strong rhythmic synaptic input from presynaptic neurons that is blocked by CNQX. The recurrent synaptic activity may arise in a negative feedback loop between a bipolar cell and an amacrine cell that exhibits resonant behavior and oscillations in membrane potential when the normal balance between excitation and inhibition is disrupted by the absence of photoreceptor input.

scholarly journals The Diversity of Intermediate Filaments in Astrocytes

Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1604 ◽  
Author(s):  
Maja Potokar ◽  
Mitsuhiro Morita ◽  
Gerhard Wiche ◽  
Jernej Jorgačevski
Keyword(s):  
Intermediate Filaments ◽  
Current Knowledge ◽  
Cell Types ◽  
Multiple Roles ◽  
Cellular Structures ◽  
Cellular Processes ◽  
Different Types ◽  
The Individual ◽  
Neuronal Functions ◽  
The Brain

Despite the remarkable complexity of the individual neuron and of neuronal circuits, it has been clear for quite a while that, in order to understand the functioning of the brain, the contribution of other cell types in the brain have to be accounted for. Among glial cells, astrocytes have multiple roles in orchestrating neuronal functions. Their communication with neurons by exchanging signaling molecules and removing molecules from extracellular space takes place at several levels and is governed by different cellular processes, supported by multiple cellular structures, including the cytoskeleton. Intermediate filaments in astrocytes are emerging as important integrators of cellular processes. Astrocytes express five types of intermediate filaments: glial fibrillary acidic protein (GFAP); vimentin; nestin; synemin; lamins. Variability, interactions with different cellular structures and the particular roles of individual intermediate filaments in astrocytes have been studied extensively in the case of GFAP and vimentin, but far less attention has been given to nestin, synemin and lamins. Similarly, the interplay between different types of cytoskeleton and the interaction between the cytoskeleton and membranous structures, which is mediated by cytolinker proteins, are understudied in astrocytes. The present review summarizes the basic properties of astrocytic intermediate filaments and of other cytoskeletal macromolecules, such as cytolinker proteins, and describes the current knowledge of their roles in normal physiological and pathological conditions.

Study of the Molecular Architecture of Keratin Filaments by Electron Microscopy

1982 ◽  
Vol 40 ◽  
pp. 118-119
Author(s):  
U. Aebi ◽  
P. Rew ◽  
T.-T. Sun
Keyword(s):  
Electron Microscopy ◽  
Structural Organization ◽  
Cell Types ◽  
Structural Features ◽  
Molecular Architecture ◽  
The Past ◽  
Keratin Filaments ◽  
Different Types ◽  
10 Nm Filaments ◽  
Different Cell Types

Various types of intermediate-sized (10-nm) filaments have been found and described in many different cell types during the past few years. Despite the differences in the chemical composition among the different types of filaments, they all yield common structural features: they are usually up to several microns long and have a diameter of 7 to 10 nm; there is evidence that they are made of several 2 to 3.5 nm wide protofilaments which are helically wound around each other; the secondary structure of the polypeptides constituting the filaments is rich in ∞-helix. However a detailed description of their structural organization is lacking to date.

“Where is Dementia?” A Systematic Literature Review Exploring Neuroanatomical Aspects of Dementia

2017 ◽  
Vol 2 (15) ◽  
pp. 9-23 ◽  
Author(s):  
Chorong Oh ◽  
Leonard LaPointe
Keyword(s):  
English Language ◽  
Signs And Symptoms ◽  
Behavioral Symptoms ◽  
Journal Articles ◽  
People With Dementia ◽  
Different Types ◽  
Precise Diagnosis ◽  
Physical Changes ◽  
The Brain ◽  
Language Literature

Dementia is a condition caused by and associated with separate physical changes in the brain. The signs and symptoms of dementia are very similar across the diverse types, and it is difficult to diagnose the category by behavioral symptoms alone. Diagnostic criteria have relied on a constellation of signs and symptoms, but it is critical to understand the neuroanatomical differences among the dementias for a more precise diagnosis and subsequent management. With this regard, this review aims to explore the neuroanatomical aspects of dementia to better understand the nature of distinctive subtypes, signs, and symptoms. This is a review of English language literature published from 1996 to the present day of peer-reviewed academic and medical journal articles that report on older people with dementia. This review examines typical neuroanatomical aspects of dementia and reinforces the importance of a thorough understanding of the neuroanatomical characteristics of the different types of dementia and the differential diagnosis of them.

The Acute Effect of Alcohol on Various Memory Processes

2010 ◽  
Vol 24 (4) ◽  
pp. 249-252 ◽  
Author(s):  
Márk Molnár ◽  
Roland Boha ◽  
Balázs Czigler ◽  
Zsófia Anna Gaál
Keyword(s):  
Low Dose ◽  
Short Term Memory ◽  
Acute Effect ◽  
Long Term Memory ◽  
Term Memory ◽  
Memory Processes ◽  
Different Types ◽  
The Brain ◽  
Legal Consequences

This review surveys relevant and recent data of the pertinent literature regarding the acute effect of alcohol on various kinds of memory processes with special emphasis on working memory. The characteristics of different types of long-term memory (LTM) and short-term memory (STM) processes are summarized with an attempt to relate these to various structures in the brain. LTM is typically impaired by chronic alcohol intake but according to some data a single dose of ethanol may have long lasting effects if administered at a critically important age. The most commonly seen deleterious acute effect of alcohol to STM appears following large doses of ethanol in conditions of “binge drinking” causing the “blackout” phenomenon. However, with the application of various techniques and well-structured behavioral paradigms it is possible to detect, albeit occasionally, subtle changes of cognitive processes even as a result of a low dose of alcohol. These data may be important for the consideration of legal consequences of low-dose ethanol intake in conditions such as driving, etc.

Types of refractive errors and methods for their diagnosis

2020 ◽  
pp. 30-36
Author(s):  
Olga Lemzyakova
Keyword(s):  
Optical System ◽  
Contact Lenses ◽  
Vision Impairment ◽  
Refractive Errors ◽  
Vision Correction ◽  
Light Rays ◽  
Different Types ◽  
Almost All ◽  
Degrees Of Severity ◽  
The Brain

Refraction of the eye means its ability to bend (refract) light in its own optical system. In a normal state, which is called emmetropia, light rays passing through the optical system of the eye focus on the retina, from where the impulse is transmitted to the visual cortex of the brain and is analyzed there. A person sees equally well both in the distance and near in this situation. However, very often, refractive errors develop as a result of various types of influences. Myopia, or short-sightedness, occurs when the light rays are focused in front of the retina as a result of passing through the optical system of the eye. In this case, a person will clearly distinguish close objects and have difficulties in seeing distant objects. On the opposite side is development of farsightedness (hypermetropia), in which the focusing of light rays occurs behind the retina — such a person sees distant objects clearly, but outlines of closer objects are out of focus. Near vision impairment in old age is a natural process called presbyopia, it develops due to the lens thickening. Both myopia and hypermetropia can have different degrees of severity. The variant, when different refractive errors are observed in different eyes, is called anisometropia. In the same case, if different types of refraction are observed in the same eye, it is astigmatism, and most often it is a congenital pathology. Almost all of the above mentioned refractive errors require correction with spectacles or use of contact lenses. Recently, people are increasingly resorting to the methods of surgical vision correction.

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